Electric furnace



i Patented Mar. 19, 1929.

UNITED STATES 1,705,717 PATENT OFFICE.

ORA A. COLBY, OF MANSFIELD, OHIO, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

i ELECTRIC FURNACE.

Application filed November 7, 1927. Serial No. 231,472.

My invention relates to furnaces and more particularly to furnaces heated by electrical resistors.

It is an object of my invention to provide,

in a furnace of the above type, heating elements adapted to cover the floor and sidewalls of the heating chamber thereof, which are removable 4as a unit therefrom. In aractieing my invention, I provide hoi-1- Zonta lyY and vertically disposed resistance elements mounted for movement as a unit into and out of operative position Within a furnace chamber, and adapted to substantially cover the floor and longitudinal side-Walls y thereof.

In the drawing,

Figure 1 is a view, in transverse vertical section, of al furnace embodying my invention, and

Fig. 2 is a view in longitudinal vertical section, taken on the lineII-II of Fig. 1.

Referring more particularly to the drawings, a furnace embodying my invention comprises side walls 2, roof 4, and bottom 6, of suitable refractory heat-insulating material One end of the furnace chamber thus defined is closed by a refractory wall 8 provided with an opening to vfacilitate the charging and discharging of the material to be heat treated. 3J The opening is normally closed during the heating operation by a removable door 10 in the usual manner. The opposite end of the furnace chamber is closed by a removable wall 12 as hereinafter described. a5 Heating of the furnace is effected by means of performed, sinuously wound, electrical resistance elements 14 adapted to be disposed to cover the floor and side walls of the furnace of electrical energy (not shown).

The means for supporting the heating elements within the furnace chamber comprises a horizontally-disposed frame 16, substantially co-extensive with the floor of the furnace, and vertically extending frames 18 and 20 secured to the upper face of frame 16 adj acent to the longitudinal edges thereof. The frames 18 and 20 are substantially co-extensive respectively with the faces of the longitudinal side-Walls of the chamber, so that, with the frames assembled and in operative position within the furnace chamber, the fioor and longitudinal side-walls thereof are substantially covered.

Any vwell known means for maintaining the edge o chamber, and suitably connectedto a sourceV frames in assembled relation may be employed, but I prefer, in the present embodiment, to weld the frames 18 and 2O to the base frame 16, and to provide tie-rods 22 ad jacent to the roof of the furnace and secured to the frames 18 and 20. -f

Electrically insulating blocks 24 are secured within the frames 16, 18 and 20, adjacent to the longitudinal yedges thereof, and are suitably recessed to receive and support the return bend portions ofthe convolutions of the resistance elements 14.

With the structure above described in `assembled relation, it is clear that the resistance heating elements are securely maintained in the frames 16, 18 and 20, and the frames are rigidly secured together to constitute a unitary structure.

The resistor supporting structure is mounted for movement, with respect to the furnace chamber', by means of flanged Wheels 28 journalled in the longitudinal faces of the frames 16 and depending plates 30 integral therewith. The Wheels 28 are adapted to ride upon rails 32 extending into the furnace chamber in longitudinally extending recesses 34 formed in the furnace side walls.

The removable wall 12 is secured to the movable resistor support by means of a depending angle plate 34 secured toa lateral the frame 16 and adapted to engage the lower edge of the wall 12 in supporting relation. Additional means for securing the wall 12 -to the resistor support comprises angles 36 extending through the wall and suitably secured to the frames 18 and 2() adjacent to the tie-rods 22. rIhe Wall 12 is thereby rigidly secured to the removable resister support and movable therewith. Slots (not shown) are cut in the lower edge of the wall 12 and plate 34 to inter-lit with the rails 32 with a yminimum of clearance, so that with the resistor support in operative position the wall 12 substantially completely closes the end of the furnace chamber.

l In operation, if access is desired to the furnace chamber to make necessary repairs to the walls thereof, or if renewal of the heating element is necessary, the resistor support and wall 12 are moved as a unit to the left of the position shown in Fig. 2, out of the furnace chamber. Free access may then be had to the interior of the furnace, if desired. On the other hand, if the heating element is de-A fective, the time lost in the renewal thereof is reduced to a minimum, since the parts Will cool relatively rapidl in the air to a point where manipulation tliereof is possible.

When the necessary renewal or repairs have been completed, the assembly is moved into operative position Within the furnace chamber, and the heating elements may be energized.

lVhile I have shown a charging opening for the furnace in the end wall 8, the furnace may he operated as ucar-bottom furnace, whereby the resistor support may be re moved from the furnace and the Work to be l1eat-treated placed thereupon and moved into the furnace therewith. Further, it is obvious that the shape and dimensions of the heating element and furnace parts may be varied within wide limits and be Within the scope of the present invention.

Various modifications may he made in my invention without departing from the spirit and scope thereof and I desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art and set forth in the appended claims.

I claim as my invention:

l. In an electric furnace, the combination with resistance elements adapted to cover the floor and side Walls thereof, of means for supporting said resistors to permit the removal thereof as a unit from the furnace chamber, said means comprising a frame, a plurality of Wheels journaled in said frame, and a track for said Wheels. p

2. A resistor support for an'electric furf nace comprising a base frame, vertically eX- tending frames secured to the longitudinal edges thereof and means tor mountingsaid frames for 4movement into and out of said furnace, said means comprising supporting wheels journalled in said base frame, and means for guiding the movement of said support with respect to said furnace.

8. A resistor support Jfor an electric furnace comprising a base frame, vertically eX- tending frames secured to the longitudinal edges thereof and means for mounting said frame for movement into and out of said furnace, said means comprising rails extending into said furnace, and flanged Wheels journalled in said base frame and adapted to cooperate With said rails.

In testimony whereof, I have hereunto subscribed my name this 25 day of October, 1927.

ORA A. COLBY. 

